You visited us 33 times! Enjoying our articles? Unlock Full Access!

Byju's Answer

Standard VIII

Chemistry

Characteristics of Chemical Reaction

Write an equa...

Question

Write an equation to show the reaction between Plaster of Paris and water?

C a S O_{4} . \frac{1}{2} H_{2} O P l a s t e r o f P a r i s + \frac{3}{2} H_{2} O W a t e r ⟶ C a S O_{4} .2 H_{2} O G y p s u m

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

C a S O_{4} . H_{2} O P l a s t e r o f P a r i s + \frac{3}{2} H_{2} O W a t e r ⟶ C a S O_{4} . \frac{5}{2} H_{2} O G y p s u m

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C a S O_{4} . H_{2} O P l a s t e r o f P a r i s + H_{2} O W a t e r ⟶ C a S O_{4} .2 H_{2} O G y p s u m

No worries! We‘ve got your back. Try BYJU‘S free classes today!

C a S O_{4} . \frac{1}{2} H_{2} O P l a s t e r o f P a r i s + \frac{1}{2} H_{2} O W a t e r ⟶ C a S O_{4} . H_{2} O G y p s u m

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is A $C a S O_{4} . \frac{1}{2} H_{2} O P l a s t e r o f P a r i s + \frac{3}{2} H_{2} O W a t e r ⟶ C a S O_{4} .2 H_{2} O G y p s u m$
Plaster of Paris when reacts with water liberating heat through crystallization. Gypsum is produced by heating plaster of paris to about 150-degree Celsius. When the dry plaster of paris powder is mixed with water it reforms into gypsum. Depending upon the temperature gypsum converts to hemihydrate or anhydrous form.
$C a S O_{4} . \frac{1}{2} H_{2} O P l a s t e r o f P a r i s + \frac{3}{2} H_{2} O W a t e r ⟶ C a S O_{4} .2 H_{2} O G y p s u m$

Suggest Corrections

Similar questions

Q. Match List - I with List - II for the compositions of substances and select the correct answer using the code given below the list:
List - I List - II
Substances Composition
(A) Plaster of paris (i)

C a S O_{4} \cdot 2 H_{2} O

(B) Epsomite (ii)

C a s O_{4} \cdot \frac{1}{2} H_{2} O

M a S O_{4} \cdot 7 H_{2} O

(D) Gypsum (iv)

M g S O_{4} \cdot H_{2} O

(v)

C a S O_{4}

$\begin{matrix} List I & List II 1. Plaster of Paris & a. C a S O_{4} .2 H_{2} O 2. Epsomite & b. C a S O_{4} .1 / 2 H_{2} O 3. Kieserite & c. M g S O_{4} .7 H_{2} O 4. Gypsum & d. M g S O_{4} . H_{2} O e. C a S O_{4} \end{matrix}$

Q. Concrete is produced from a mixture of cement, water and small stones. A small amount of gypsum,

C a S O_{4} \cdot 2 H_{2} O

is added in cement production to improve the subsequent hardening of concrete.
The elevated temperature during the production of cement may lead to the formation of unwanted hemihydrate

C a S O_{4} \cdot \frac{1}{2} H_{2} O

according to reaction.

C a S O_{4} \cdot 2 H_{2} O (s) \to C a S O_{4} \cdot \frac{1}{2} H_{2} O (s) + \frac{3}{2} H_{2} O (g)

The

Δ_{f} H^{⊖}

C a S O_{4} \cdot 2 H_{2} O (s), C a S O_{4} \frac{1}{2} H_{2} O (s), H_{2} O (g)

are

- 2021.0 k J m o l^{- 1}

- 1575.0 k J m o l^{- 1}

and

- 241.8 k J m o l^{- 1}

respectively. The respective values of their standard entropies are

194.0

130.0

and

188.0 J K^{- 1} m o l^{- 1} .

R = 8.314 J K^{- 1} m o l^{- 1} = 0.0831 L b a r m o l^{- 1} K^{- 1}

Answer the follwoing questions on the basis of above information.

Heat change occuring during conversion of

1 K g

C a S O_{4} \cdot 2 H_{2} O (s)

(molar mass 172 g mol

^{- 1}

) of

C a S O_{4} \cdot \frac{1}{2} H_{2} O (s)

is equal to:

Q. Question 32
Match the important chemicals given in Column I with the chemical formulae given in Column II.

Join BYJU'S Learning Program